Decide if you wish to buy a Harley or a Ducati.
Ios and Android are 2 different products.
As the number of cores increases, so does the battery consumption.
More Cores = More chances of your battery having loose motions.
Buy Ios if
-You wanna show off "I have an Iphone"
-Play games
-Music Fan
-Need very crisp images/videos
-Can't stand lags or hangs or crashes
-Can bear with no sms delivery reports (Yeah, atleast not out of the box)
Buy Android if
-Want an open source phone
-Don't mind charging the phone often (Now again, this varies from model to model, and even user to user, I never managed to get good battery life out of a brand new phone on a custom ROM)
-Want to toy with custom ROM's
-Can bear Hangs, Lags and Force Close errors at times.
-Are ok removing the battery to stabilize the device, if required
Remember,
A touch screen device has a big screen and eats battery more than a non touch phone, even when Wifi, GPS and GPRS is off.
Have a look at HTC One (Its around 18k I think) is a good deal for now
HTC One V: Price in India, Reviews, Specification: Flipkart.com
(HTC Comes with an ICS out of the Box, but if I remember this one is single core)
Alternatively look at this
Sony Xperia Sola: Price in India, Reviews, Specification: Flipkart.com
(Has Dual core but v2.3, though sony promised ICS Update)
Lastly there are some more Sony devices under the 'Xperia' table (Too many models to remember, so please do your own search)